diff --git a/paddlenlp/prompt/prompt_tokenizer.py b/paddlenlp/prompt/prompt_tokenizer.py
index 8e41162c5ab6..1e50c92c74dd 100644
--- a/paddlenlp/prompt/prompt_tokenizer.py
+++ b/paddlenlp/prompt/prompt_tokenizer.py
@@ -129,17 +129,15 @@ def _create_max_lengths_from_do_truncate(self, part_text: List[str], part_do_tru
         text_length = sum([len(x) for x in part_text])
         num_special_token = self.tokenizer.num_special_tokens_to_add()
         max_length = self.max_length - num_special_token
+        max_lengths = [len(part) for part in part_text]
         if text_length <= max_length:
-            return [None] * len(part_text)
-        max_lengths = [None for _ in range(len(part_text))]
+            return max_lengths
         do_truncate = [int(x) for x in part_do_truncate]
 
         # Remove parts that can not be truncated.
         for index, part in enumerate(part_text):
             if not part_do_truncate[index]:
                 max_length -= len(part)
-            else:
-                max_lengths[index] = len(part)
         if sum(do_truncate) == 0:
             logger.warning(
                 f"Can not truncate the sequence with length {text_length}. Set more `truncate` attributes as True."
@@ -154,7 +152,6 @@ def _create_max_lengths_from_do_truncate(self, part_text: List[str], part_do_tru
             for index, part in enumerate(part_text):
                 if do_truncate[index] == 1 and len(part) <= avg_max_length:
                     do_truncate[index] = 0
-                    max_lengths[index] = len(part)
                     max_length -= len(part)
                     has_short = True
         if max_length < 0: